Product and process for preparing 1, 4, 2-dioxaborolanes



United States Patent 3,189,627 PRODUCT AND PROCESS FOR PREPARING1,4,2-DIOXABOROLANES Melville E. D. Hillman, Richmond, Calii'., assignorto E. I. du Pont de Nemours and Company, Wilmington, Del., a corporationof Delaware No Drawing. Filed June 4, 1962, Ser. No. 199,585 7 Claims.(Cl. 260462) This invention relates to chemical compounds and, moreparticularly, to a new class of organic boron compounds and a processfor their preparation.

It is Well-known that the addition of boron compounds to gasolineproduces beneficial effects on engine performance including an increasein octane number. However, few boron compounds are known which aresufficiently soluble to be incorporated into gasoline and which arestable to decomposition after incorporation.

This invention provides a new class of liquid boron compounds which aresoluble in organic solvents, including gasoline, and which have theproperty of increasing the octane number of gasoline when incorporatedtherein. Certain compounds of this invention are also useful asfungicides.

The compounds of the present invention are 1,4,2-di oxaborolanes of theformula:

CHB

RB-O

wherein R is a 1 to 12 carbon atom radical bonded to the remainder ofthe compound through aliphatic carbon and R is a hydrogen, alkyl orchloro-alkyl radical of up to 12 carbon atoms. In namingthedioxaborolanes of the above formula, the ring positions are numberedclockwise beginning with the oxygen adjacent to the boron atom. Thesubstituents in the two and three positions are preferably hydrocarbonradicals free of ethylenic unsaturation, especially alkyl radicals. TheR substituents in the two and three positions can be the same ordifferent, and include, for example, alkyl such as methyl, ethyl,propyl, isopropyl, n-butyl, secondary butyl, isobuty-l, n-amyl,secondary amyl, isoamyl, n-hexyl, isohexyl, n-heptyl, n-octyl, n-nonyl,n-decyl, n-undecyl or n-dodecyl; cycloalkyl such as cyclohexyl orcyclopentyl;

(cycloalkyl) alkyl such as cyclohexylmethyl or cycl0l1exylethyl, oraralkyl such as phenylethyl'or phenylpropyl. As indicated above, R canbe hydrogen, alkyl, preferably 1 to 4 carbon alkyl, or chloroalkyl,including polychloroalkyl, e.g., diand trichloroalkyl as well asmonochloroalkyl.

The 1,4,2-dioxaborolanes of this invention are prepared by heating aborane of the formula R B with an aldehyde of the formula wherein R andR have the significance noted above, with carbon monoxide at atemperature of about from 25 to 125 C. Illustrative boranes of theformula R B which can be employed in the reaction includetrimethylborane, triethylborane, tri-n-propylborane, triisopropylborane,trinabutylborane, tri-n-decylborane, methyldiethylborane,dimethylethylborane, diethyl-n-propylborane,diethylcyclohexylmethylborane, diethylphenylethylborane, etc. Illustrative aldehydes include formaldehyde, acetaldehyde,chloroacetaldehyde, chloral, proprionaldehyde and butyraldehyde.

Although less than a stoichiometric quantity can be employed, usuallyfor economic reasons the quantity of reactant.

3,189,627 Patented June 15, 1965 aldehyde should be at least vl mole permole of the borane Although usually less than about 5 moles of aldehydeper mole of the borane are employed, there is no upper limit on thequantity of aldehyde used except that imposed by economics of aldehyderecovery and the space-time yield obtained in the reaction vessel.

The pressure of carbon monoxide used, that is, therea'ction pressure,can vary from about 1 to about 1000 atmospheres. Higher pressures can beused but steel equipment suitable for use with higher pressures isinordinately expensive. In general, the preferred range of pressure isfrom about 100 atmospheres to about 900 atmospheres.

The carbon monoxide may be used alone or admixed with gases inert to thereaction such as nitrogen. Of course, the partial pressure of CO must behigh enough to give a reasonable reaction rate, for example, on theorder of at least one atmosphere during the entire reaction.

The temperature used in the process can range from about 25 to about 125C. or higher. The preferred range of temperature is from about 35 toabout C. Below 25 C. the reaction goes at such 'a slow rate as to beuneconomic and above 125 C. there is danger of decomposition oftheproducts.

The reaction can be carried out in the presence or absence of water ororganic solvent. Thus, for example, the aldehyde can be anhydrous or,alternately, the aldehyde can be introduced as a hydrate or in aqueoussolution. Similarly, the reaction can be carried out in the presence oforganic solvents, preferably inert solvents, such as acetone, alcohol,dioxane, ether, n-pentane, benzene, toluene, xylene, or mixturesthereof.

The dioxaborolanes of the present invention are isolated by conventionaltechniques, generallydistillation at reduced pressure. If water'ispresent in the reaction mixture, they can be extracted with a Waterimmiscible or- A stainless steel pressure vessel is charged with partsof aqueous 37% formaldehylde and 54.6 parts of triethylborane. Thevessel is pressurized with carbon monoxide to a pressure of 700atmospheres and heated with agitation at 50 C. for 1 hour. The reactionmixture is extracted with ether, the extract dried over MgSO anddistilled to give 40.5 parts (48% yield) of 2,3,3-triethyl-l,4,2-dioxaborolane boiling at 50 at 0.2 mm.

Hydrolysis of the dioxaborolane with aqueous sodium hydroxide gives (C HCI-IOH, a secondary alcohol, indicating the presence of (C H C in thecompound. Infrared spectra show the presence of B-O bonds and CO bonds.

A 48% yield of 2,3,3,5,6,6-hexaethyl-2,S-diboradioxane is also obtainedas a by-produot in the preparation of the dioxoborolane described above.

Example 2 A stainless steel pressure vessel is charged with 100 parts of37% aqueous formaldehyde and 79.0 parts of tri-isobutylborane. Thevessel is pressurized with carbon monoxide to 700 atmospheres. It isthen heated and agitated for one hour at 50 C. The reaction mixture isextracted with ether, the extract dried over MgSO and distilled to givea 37% yield of 2,3,3-triisobutyl-1,4,2-dioxaborolane, a clear colorlessliquid boiling at 7585 C. at 0.65 mm. pressure.

f The procedure of Example 1 is repeated using '50 of triethylboraneand100 parts of chloral hydrate.

Example 3 7 ethyD-borane, tricyclohexylbora ne,

parts A 62%. yield of 2,3,etriethyl-5-trichloromethyl-1,4,2-dioxaborolane boiling at 100 at 1.2 mm. is obtained. Elemental analysis showsthe following:

Calculated for C H BO Cl C, 39.53; H, 5.90; B,

3.96. F011nd:' C, 39.65; H, 5.87; B, 3.81.

Example 4 The procedure-of Example 1 is repeated using 50 parts oftri-n-butylborane and 100 parts of chloral hydrate. A 69% yield of2,3,3-tri-n butyl-5-trichloromethyl 1,4,2- dioxaborolane boiling at 110'C. at 0.1 mm. is obtained. iElemental analysis shows the following:

Calculated for C H BO Cl C, 50.38; H, 7.8; B, 3.03.

f lFound: 3,5045; H, 7.88; B, 3.21. r e

7 Example; I g The procedure'of Examplel is repeated using 100 parts of40% aqueous Z-chloioacetzildehyde and parts. of

triethylborane. A 92% yield of2,3,3-t'1iethyl-5-chloromethyl-1,4,2-dioxaborolane boiling at C. at 0.2mm.

. ,is obtained. Elemental analysis. shows the following: Y

' Calculated for C H BO Cl: C, 52.85; H, 8.87; B, 5.29. Found: 52.56; H,9.04; B, 5.04.

Example 6 f The'p rocedure of Example 1 is repeated using 100 parts ofn-butyraldehyde and 50 parts of tn'ethylborane.

A yield of 2,3,3-triethyl-5-propyl-1,4,2-dioXabor0- lane boiling at 55C. at.0.5 mm. is obtained. Analysis reveals the following:

' Calculated for 011112530 0, 66.69; H, 11.70; B, 5.46. Found: '0,66.36; H, 11.43; B, 5.72. g

Example 7 I The procedure of Example 1'is repeated using parts ofacetaldehyde and 50 parts of triethylboranef A 74% yield of 2,3,3 -triethyl-5-met-hyl-l,4,2-dioxaborolane boiling at 35 C. at 0.25 mm. isobtained. Elemental analysis reveals the following: 7

Calculated for C H BO C, 63.56; H, 11.26; B, 6.36. Found: C, 63.71; H,11.24; B, 6.51: 7

'When triethylbor-ane is replaced by tri(phenylortri(cyclohexylmethyl)borane in the above proceduresimilar results areobtained.- W l i The compounds and process of the invention have been 7demonstrated by the above examples. Many othermod- V ifications areobvious to'those skilled in the art without departing from the inventiveconcept.

I claim: a 1 1. Acompound of the formula j R3040 I N 101112 RB-O/wherein R is a to 12 carbon atom radical bonded to the ring throughaliphatic carbon, and R is selected from the group. consisting ofhydrogen, alkyl 'and chloralkyl radicals of up to 12 carbon atoms. a r2. A compound of claim 1 wherein R is alkyl and R is hydrogen. a

0 3. 'A compound of claim lwherein R is alkyl and R is Vtrichloromethyl. H I

4. A compound of claim 1 wherein R is alkyl and R is monochloromethyl; VI a 5. A compound of claim 1 wherein R'is alkyl and Ris .1 to 4 carbon.atom alkyl.

6. A process for preparing 1,4,2-dioxaborolaneswhich comprises heating aborane "of the fo'rmula R B .with an' aldehyde of the formula g :andcarbon monoxide at a temperature of-25 to and a carbon monoxide pressureof from about 1 to about I 1000 atmospheres, R being a 1 to'lZcarbon-atom radical bonded to boron through aliphatic carbon, @R'f beingselected from the group consisting of hydrogen, alkyl and chloroalkyl ofup to 12 carbon atoms. 7 7. A- process of claim 6 wherein the reactiontemperapressure is about ture is 35to 75 C. and the reaction from 100 to900 atmospheres.

7 References Cited by the Examiner v UNITED STATES PATENTS V 7 3,006,961'10 61' Reppe et al. 260+6065 CHARLESB. PARKER, Primary Examiner.

1. A COMPOUND OF THE FORMULA
 6. A PROCESS FOR PREPARIG1,4,2-DIOXABOROLANES WHICH COMPRISES HEATING A BORANE OF THE FORMULA R3BWITH AN ALDEHYDE OF THE FORMULA